284 BYZANTINE CHURCHES 'CHAP,
of the ground. It is a single hall m. 8.80 in length and m. 3,70 wide, terminating in a bema and a circular apse in brick. Over the bema is a barrel vault. A dome, without drum or windows, resting on two shallow flat arches in the lateral walls and two deep transverse arches strengthened by a second order of arches, covers the building. In the wall towards the north-west there is a window between two low niches ; and a similar arrangement is seen in the opposite wall, except that the door which communicated with the residence occupies the place of the window. The apsidal chambers, usual in a church, are here represented by two niches in the bema. Externally the apse shows five sides, and is decorated by a flat niche pierced by a single light in the central sides and a blind concave niche, with head of patterned brickwork, in the two adjacent sides. The dome, apse, vaults, and transverse arches are in brick, laid in true radiating courses. The absence of windows in the dome is an unusual feature, which occurs also in the angle domes of S. Theodosia. The pendentives are in horizontal courses, corbelled out to the centre, and at each angle of the pendentives is embedded an earthenware jar, either for the sake of lightness, or to improve, as some think, the acoustics of the building. This story of the chapel is used as a hayloft.
A careful survey of the building shows clearly that the domical character of the chapel is not original, and that the structure when first erected was a simple hall covered with a wooden roof. Both the shallow wall arches and the deep transverse arches under the dome are insertions in the walls of an older fabric. They are not supported on pilasters, as is the practice elsewhere, but rest on corbels, and, in order to accommodate these corbels, the lateral niches, originally of the same height as the central window, have been reduced in height. A fragment of the original arch still remains, cut into by the wall arch of the dome. The flat secondary arches crossing the chapel at each end are similarly supported on corbels.
This view is confirmed by the examination of the plaster left upon the walls. That plaster has four distinct coats or